KR20060132139A - Method for manufacturing of liquid crystal display device - Google Patents

Abstract

A manufacturing method of an LCD is provided to improve uniformity of an image quality by uniformly performing alignment even on a large-sized substrate by attaching a rubbed alignment layer onto the substrate. A first alignment layer(112) is attached onto a first substrate(101). A second alignment layer(205) that has been aligned is attached onto a second substrate(201) corresponding to the first substrate. The first substrate and the second substrate are bonded together such that the first alignment layer and the second alignment layer face each other. A liquid crystal layer is formed between the first substrate and the second substrate.

Description

Method for manufacturing of liquid crystal display device

1 is a cross-sectional view showing a general liquid crystal display device

2A to 2C are views for explaining an alignment film rubbing process according to the prior art;

3 is a view for explaining a rubbing failure in the rubbing process according to the prior art

4A to 4F are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

5 is a schematic configuration diagram showing a general alignment film printing apparatus;

 6 is a view for explaining a liquid crystal dropping process in the method of manufacturing a liquid crystal display device according to the present invention.

Explanation of symbols for the main parts of the drawings

101: first glass substrate 104: gate electrode

111 pixel electrode 112 first alignment layer

201: second glass substrate 204: common electrode

205: second alignment layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a method for manufacturing a liquid crystal display device to improve the rubbing uniformity of an alignment layer according to the enlargement of a substrate.

In general, liquid crystal display devices have characteristics such as low voltage driving, low power consumption, full color, light weight, and small size, and thus are widely used in clocks, calculators, PC monitors, laptops, and so on. Increasingly, applications are being used in mobile phones and the like.

Such a liquid crystal display device is largely divided into a liquid crystal display panel for displaying an image and a circuit unit for driving the liquid crystal display panel.

The liquid crystal display panel includes a TFT substrate on which a thin film transistor array is formed, a CF substrate on which a color filter array is formed, and a liquid crystal layer formed between the two substrates.

On the other hand, an alignment film is formed on the surfaces of the opposing TFT substrate and the CF substrate, respectively, to determine the alignment direction of the liquid crystal layer.

The TFT substrate includes a plurality of gate lines arranged in one direction at a predetermined interval, a plurality of data lines arranged in a direction perpendicular to the gate lines to define a pixel region, and formed in the pixel regions. A plurality of pixel electrodes for displaying an image and a pixel area in a portion where the gate lines and the data lines cross each other, and are turned on / off by a driving signal of the gate lines to transmit an image signal of the data line to each pixel electrode; A plurality of thin film transistors are provided.

The CF substrate may further include a black matrix layer that blocks light in portions other than the pixel region, an R, G, and B color filter layer formed in portions corresponding to the pixel regions to implement color, and the color filter layer. It is provided with a common electrode formed on the front surface. Of course, in the liquid crystal display of the IPS (In Plane Switching) mode, a common electrode may be formed on the TFT substrate.

1 is a cross-sectional view showing a general liquid crystal display device.

As shown in FIG. 1, a gate electrode 11 made of a conductive material such as a metal is formed in a predetermined region on the transparent first substrate 10, and the first substrate 10 including the gate electrode 11 is formed. A gate insulating film 12 made of a silicon nitride film (SiNx) or a silicon oxide film (SiO ₂ ) is formed over the entire surface of the gate.

Next, an active layer 13 made of amorphous silicon is formed on the gate insulating layer 12 on the gate electrode 11, and an ohmic contact layer made of amorphous silicon doped with impurities in both units of the active layer 13. 14 is formed.

Subsequently, source and drain electrodes 15 and 16 made of a conductive material such as a metal are formed on the ohmic contact layer 14, and the source and drain electrodes 15 and 16 are connected to the gate electrode 11. Together, it forms a thin film transistor (T).

Although not shown in the drawing, the gate electrode 11 is connected to the gate wiring, the source electrode 15 is connected to the data wiring, and the gate wiring and the data wiring are orthogonal to each other to define the pixel region. .

Subsequently, a protective film 17 made of a silicon nitride film, a silicon oxide film, or an organic insulating film is formed on an entire surface of the first substrate 10 including the source and drain electrodes 15 and 16, and the protective film 17 is formed on the drain. The contact hole 18 is provided so that the surface of the electrode 16 may be exposed to a predetermined portion.

A pixel electrode 19 made of a transparent conductive material is formed in the pixel area above the passivation layer 17, and the pixel electrode 19 is connected to the drain electrode 16 through the contact hole 18.

Subsequently, a first alignment layer 20 made of a material such as polyimide and formed to have a predetermined direction is formed on the pixel electrode 19.

On the other hand, the second substrate 31 is disposed above the first substrate 10 at regular intervals and spaced apart from the first substrate 10.

In addition, a black matrix 32 is formed at a portion of the lower portion of the second substrate 31 that corresponds to the thin film transistor T. Although not illustrated, the black matrix 32 covers portions other than the pixel electrode 19. .

Subsequently, a color filter 33 is formed below the black matrix 32, and the color filter 33 sequentially repeats three colors of red (R), green (G), and blue (B). One color corresponds to one pixel area.

Subsequently, a common electrode 34 made of a transparent conductive material is formed under the color filter 33, and a lower portion of the common filter 34 is formed of a material such as polyimide and has a predetermined direction. The two alignment film 35 is formed.

The liquid crystal layer 40 is injected between the first alignment layer 20 and the second alignment layer 35.

Such a liquid crystal display includes an array substrate manufacturing process for forming a thin film transistor and a pixel electrode, a color filter substrate manufacturing process for forming a color filter and a common electrode, an arrangement of two manufactured substrates, an injection and encapsulation of a liquid crystal material, and a polarizing plate attached. It is formed by a liquid crystal panel process consisting of.

Hereinafter, a method of rubbing an alignment layer of a liquid crystal display according to the prior art will be described with reference to the accompanying drawings.

2A to 2C are views for explaining an alignment film rubbing process according to the prior art.

That is, FIG. 2A is a perspective view showing the alignment film rubbing device, FIG. 2B is a side view showing the alignment film rubbing device, and FIG. 2C is a plan view showing the alignment film rubbing device.

As shown in FIGS. 2A to 2C, the rubbing device includes a cylindrical rubbing roller 61, a rubbing cloth 62 attached to an outer circumferential surface of the rubbing roller 61 by using double-sided tape, and the rubbing roller. Rotation shaft 63 is connected to both sides of the support 61 to support the rubbing roller 61 and rotates in one direction, and a rotation motor 66 connected to the rotation shaft 63 to rotate the rotation shaft 63. It is.

The rubbing method of the alignment film using the rubbing device configured as described above is as follows.

That is, the substrate 64 on which the alignment film 65 is formed is mounted on the upper surface of the stage 60, and the stage 60 is advanced in the direction of the arrow by rotating the driving roller by the power of the driving motor (not shown).

Here, the drive motor is a motor for moving the stage 60 in one direction.

At this time, the rubbing roller 61 connected to the rotation shaft 63 is in contact with the alignment film 65 of the substrate 64 mounted on the stage 60 moving forward from the bottom thereof, and is rotated in one direction by the rotation motor 66. Groove to form grooves on the surface of the alignment film (65).

That is, the rubbing process proceeds by rotating a cylindrical rubbing roller 61 wound with a rubbing cloth 62 such as rayon or nylon and applying a physical friction to the surface of the alignment layer 65 to rub it.

On the other hand, in order to have a uniform display characteristics in the liquid crystal display device, it is important to form a groove uniformly in a large area, which is the polymer chain on the alignment film surface by rubbing the surface of the alignment film with a rubbing cloth 62 at a uniform pressure and speed. It is possible by aligning in a certain direction.

On the other hand, in order to have a uniform display characteristics, it is important to form a groove uniformly in a large area, which is possible by aligning the polymer chain on the alignment film surface in a certain direction by rubbing the surface of the alignment film with a rubbing cloth at a uniform pressure and speed. .

The above-described conventional method of rubbing an alignment film of a liquid crystal display device by rubbing the alignment film with a rubbing cloth to uniformly distribute the liquid crystal molecules and to align the alignment in the same direction to perform uniform display over the entire surface of the liquid crystal display device. The purpose is to make it.

By the way, in the liquid crystal display device in recent years, the size of the width | variety and the vertical dimension is also made into 1100 mm or more, and the rubbing roller used for the rubbing apparatus of an orientation processing process is also enlarged by this.

In this case, as shown in Fig. 3, in the rubbing roller 61 using the metal rubbing roller 61 as in the prior art, as the length of the cylinder becomes longer, the central portion in the longitudinal direction of the rubbing roller 61 has its own weight. Is bent, the alignment film 65 formed on the substrate 64 is rubbed with uneven pressure, and as a result, uniformity is lost in the display on the entire surface of the liquid crystal display, resulting in damage to the display quality.

Moreover, when the orientation process is performed with the rubbing roller 61 which adhered the rubbing cloth 62 with the usual adhesive to the metal rubbing roller 61, the rubbing cloth 62 and the orientation film | membrane by rotation of the said rubbing roller 61 are carried out. Electrostatics are generated by the friction of the 65, and dust and particles present in the air and particles missing from the rubbing cloth 62 and the like are adsorbed onto the alignment layer 65, so that the presence of liquid crystal is inhibited. It becomes indication that part such as) exists.

Disclosure of Invention The present invention has been made to solve the above problems, and an object thereof is to provide a method of manufacturing a liquid crystal display device in which a rubbing process is easily performed even for an enlargement of the liquid crystal display device.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, the method including attaching a first alignment layer that is aligned on a first substrate, and performing alignment treatment on a second substrate corresponding to the first substrate. Attaching the first and second alignment layers to each other, bonding the first and second substrates so that the first and second alignment layers face each other, and forming a liquid crystal layer between the first and second substrates. Characterized in that it comprises a step.

Hereinafter, a method of manufacturing a liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

4A to 4F are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

As shown in FIG. 4A, the conductive metal is deposited on the first glass substrate 101, and the conductive metal is patterned by using a photo and etching process to form a gate line (not shown) and one direction in the gate line. A protruding gate electrode 104 is formed.

The conductive metal may be a metal such as aluminum (Al), chromium (Cr), molybdenum (Mo), tungsten (W).

As shown in FIG. 4B, a gate insulating film 105 is formed on the entire surface of the first glass substrate 101 on which the gate electrode 104 is formed.

The gate insulating layer 105 may use a silicon nitride layer (SiNx) or a silicon oxide layer (SiO ₂ ).

Next, a semiconductor layer (amorphous silicon + impurity amorphous silicon) is formed on the gate insulating film 105.

Subsequently, the semiconductor layer is patterned by photo and etching processes to form an active layer 106 having an island shape on the gate electrode 104.

As shown in FIG. 4C, a conductive metal is deposited on the entire surface of the first glass substrate 101 including the active layer 106, and at predetermined intervals on both sides of the active layer 106 through photo and etching processes. The spaced source electrode 107 and the drain electrode 108 are formed, respectively.

The source electrode 107 is a portion protruding from the data line orthogonal to the gate line.

As shown in FIG. 4D, an inorganic insulating film of a silicon oxide film (SiOx) and a silicon nitride film (SiNx), an organic insulating material such as BCB (Benzo Cyclo Butene), acryl, polyimide, etc., is formed on the entire surface of the first glass substrate 101. Deposition to form a protective film 109, and selectively removes the protective film 109 so as to expose a predetermined portion of the surface of the drain electrode 108 to form a contact hole 110.

The protective layer 109 is formed for the purpose of protecting the active layer 106 from external moisture or foreign matter.

As shown in FIG. 4E, a transparent metal such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the entire surface of the first glass substrate 101 including the contact hole 110, and photo and etching are performed. The transparent metal is selectively removed through the process to form the pixel electrode 111 connected to the drain electrode 108.

The first alignment layer 112 having the completed alignment treatment is attached to the entire surface of the first glass substrate 102 including the pixel electrode 111.

Here, the alignment process is completed, the first alignment layer 112 is formed by depositing a polyimide-based organic material on an arbitrary mother substrate (not shown) having a flat surface to form an alignment layer, An orientation treatment is performed on the surface of the alignment film by using a general rubbing cloth.

As shown in FIG. 4F, a black matrix layer 202 for preventing light leakage and R, G for implementing colors on the second glass substrate 201 corresponding to the first glass substrate 101 are provided. A color filter layer 203 made of a color filter element of B and an overcoat layer (not shown) are sequentially stacked.

Here, the color filter layer 203 is formed by a dyeing method, a printing method, a pigment dispersion method, an electrodeposition method and the like. A common method currently used for forming a color filter is a pigment dispersion method.

The common electrode 204 is formed on the entire surface of the second glass substrate 201 including the overcoat layer, and the second alignment layer 205 having completed the alignment process is attached to the common electrode 204.

The second alignment layer 205 on which the alignment process is completed may form an alignment layer by depositing a polyimide-based organic material on an arbitrary mother substrate (not shown) having a flat surface. An orientation treatment is performed on the surface of the alignment film by using a general rubbing cloth.

Although not shown in the drawings, the common electrode 204 and the pixel electrode 111 may be applied to the first glass substrate 101.

That is, the common electrode 204 and the pixel electrode 111 may be formed on the same layer as the gate line or the data line, and the common electrode 204 may be formed on the same layer as the data line and the pixel electrode 111. ) May be formed on the passivation layer 109.

In addition, the first and second alignment layers 112 and 205 attached to the first and second glass substrates 101 and 201 after the alignment process is completed are polymer materials, and the alignment liquid material may be polyamide or polyimide. Compounds, polyvinyl alchol (PVA), polyamic acid (Polymic Acid) can be used to form an alignment solution, polyvinyl cinnamate (PVC), poly siloxane cinnamate (PSCN) or cellulose cinnamate (CelCN) -based compounds Photoreactive materials such as can be used.

In addition, the method of attaching the first and second alignment films 112 and 205 subjected to the alignment treatment according to the present invention onto the first and second glass substrates 101 and 201 is performed by applying a heat treatment at about 200 ° C.

After the first glass substrate 101 and the second glass substrate 201 are bonded together, a liquid crystal is injected therebetween to form the liquid crystal layer 300.

5 is a schematic configuration diagram showing a general alignment film printing apparatus.

As shown in FIG. 5, the alignment film printing apparatus of a general liquid crystal display device includes a dispenser 56 for supplying an alignment liquid and a printing roll 51 surrounded by a printing mask 52 to print the alignment liquid on the upper surface of the mother substrate 50. An anilox roll 53 for depositing an alignment solution on the printing mask 52, a doctor blade 54 for uniformly embedding the alignment solution provided from the dispenser 56 on the anilox roll 53, The stage 58 on which the mother substrate 50 is loaded and seated, the loading device 60 for loading the mother substrate 50 on the stage 58, and the mother substrate 50 on which the alignment film is printed are staged. And an unloading device 62 for unloading on 58.

Here, the mother substrate 50 is loaded on the stage 58 by the loading device 60 and then unloaded on the stage 58 by the unloading device 62 when the alignment film printing is completed.

In addition, the stage 58 is conveyed in one direction by a driving roller 59 which is connected to a driving motor (not shown) and rotates.

In addition, the dispenser 56 is installed on the anilox roll 53 and moved left and right by a driving device (not shown) to supply the alignment liquid to the outer peripheral surface of the anilox roll 53.

In addition, the doctor blade 54 includes a rectangular plate-shaped blade 57 and a blade support 55 for supporting the blade 57. The blade 57 is fixed to the blade support 55 so as to be spaced apart from the outer circumferential surface of the anilox roll 53 to have a predetermined gap.

Accordingly, the blade 57 serves to evenly spread the alignment liquid supplied from the dispenser 56 to the outer circumferential surface of the anilox roll 53 in a state where the blade 57 has a predetermined gap with the outer circumferential surface of the anilox roll 53.

Further, the anilox roll 53 contacts the outer circumferential surface of the print master 52 of the printing roll 51 so that the alignment liquid evenly spread on the outer circumferential surface thereof by the doctor blade 54 to print the mask of the printing roll 51. It serves to deposit on (52).

In addition, the printing mask 52 is attached to the outer peripheral surface of the printing roll 51 as a rubber material. The print mask 52 is in contact with the outer circumferential surface of the anilox roll 53 by the rotation of the printing roll 51 so that the alignment liquid printed on the outer circumferential surface of the anilox roll 53 may be formed on the mother substrate 50. Print

Such a conventional alignment film printing apparatus and method has an orientation liquid, such as a polyimic acid solution, between the doctor roll 54 and the anilox roll 53 by means of the dispenser 56 which moves left and right to supply the alignment liquid. After it has passed on, it flows down by the rotation of the doctor roll 54 and the anilox roll 53, and is then deposited on the printing mask 52 wound on the outer circumferential surface of the printing roll 51. At this time, when the printing roll 51 starts to rotate, power is applied to the driving motor to rotate the driving roller 59.

Subsequently, the stage 58 on which the LCD substrate 50 is loaded by the rotation of the driving roller 59 is conveyed in one direction at a constant speed. Here, the rotational speed of the printing roll 51 and the operation speed of the stage 57 are set equal to each other.

The print mask 52 having received all of the alignment liquid is in contact with the mother substrate 50 transported by the stage 58 while being rotated by the rotation of the printing roll 51 so as to be thin on the surface of the mother substrate 50. The alignment liquid of thickness is printed.

Subsequently, when the alignment film is printed on the mother substrate 50, the unloading device 62 unloads the mother substrate 50 seated on the stage 58 to the outside. At this time, the stage 58 is returned to the loading device 60 by the reverse rotation of the drive roller 59 after the mother substrate 50 is unloaded by the unloading device 62. Then, the alignment liquid is printed on the other mother substrate 50 by the process as described above.

As described above, the mother substrate 50 on which the alignment liquid is formed is moved to a rubbing device as shown in FIGS. 2A to 2C, and rubbing is performed on the surface of the alignment liquid.

Meanwhile, in the detailed description of the present invention, the liquid crystal layer 300 is formed by the injection method, but the liquid crystal layer 300 may be formed by the dropping method without being limited thereto.

That is, FIG. 6 is a view for explaining a liquid crystal dropping process in the method of manufacturing a liquid crystal display device according to the present invention.

First, the liquid crystal injection method cuts into a unit panel and maintains a vacuum state between the two substrates so that the liquid crystal inlet is immersed in or contacted with a liquid crystal container containing a liquid crystal material so that the liquid crystal is injected. Degrades. In addition, when a large area liquid crystal display device is manufactured, liquid crystal is not completely injected into the panel, which may cause a defect.

Therefore, the liquid crystal dropping method does not inject the liquid crystal due to the pressure difference between the inside and the outside of the panel, but directly drops the liquid crystal onto the large-area glass substrate, and uniformly distributes the liquid crystal dropped by the bonding pressure of the substrate. This is to form a liquid crystal layer.

That is, before bonding the 1st glass substrate 101 and the 2nd glass substrate 201, the liquid crystal 300 is dripped at the center part of the 1st glass substrate 101 in a drop shape. In addition, the liquid crystal 300 may be dropped on the second glass substrate 201 without being limited thereto.

In other words, any of the first glass substrate 101 and the second glass substrate 201 may be used as the substrate to be subjected to liquid crystal dropping in the liquid crystal dropping method. However, when the two substrates are bonded, the substrate on which the liquid crystal 300 is dropped must be placed on the lower portion.

In this case, the seal pattern 206 is applied to the outer region of the second glass substrate 201 to apply a constant pressure to the first glass substrate 101 and the second glass substrate 201, thereby providing a first glass substrate 101. ) And the second glass substrate 201 are bonded together, and at the same time, the liquid crystal droplets are spread out by the pressure, and a liquid crystal layer having a uniform thickness is formed between the first glass substrate 101 and the second glass substrate 201. do.

In other words, the biggest feature of the liquid crystal dropping method is that the liquid crystal 300 is dropped on the first glass substrate 101 before the bonding process, and then the seal pattern 206 is formed on the second glass substrate 201. The first glass substrate 101 and the second glass substrate 201 are bonded to each other.

Meanwhile, both the seal pattern 206 and the liquid crystal 300 may be formed on the first glass substrate 101.

Since the liquid crystal dropping method directly drops the liquid crystal onto the substrate for a short time, not only can the liquid crystal layer formation of a large area liquid crystal display device proceed very quickly, but also only the required amount of liquid crystal is directly dropped onto the substrate. Since it is possible to minimize the consumption of the liquid crystal display device can significantly reduce the manufacturing cost.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in Esau.

As described above, the manufacturing method of the liquid crystal display according to the present invention has the following effects.

First, the uniformity of the image quality can be improved by attaching the alignment film on which the rubbing process is completed and performing the alignment treatment even on a large-area substrate.

Second, when a defect occurs during the alignment process, only the alignment layer is released and a new alignment-treated alignment layer is attached to reduce the manufacturing cost of the display device.

Third, the rubbing nonuniformity caused by the enlargement of the substrate may be solved by attaching the alignment layer on which the rubbing process is completed, and the alignment nonuniformity of the stepped portion that occurs when the rubbing process is performed in a patterned state may be solved.

Claims (2)

Attaching the alignment-oriented first alignment layer on the first substrate; Attaching an alignment-treated second alignment layer on the second substrate corresponding to the first substrate; Bonding the first substrate to the second substrate such that the first alignment layer and the second alignment layer face each other; And forming a liquid crystal layer between the first substrate and the second substrate. The method of claim 1, wherein the first alignment layer and the second alignment layer are attached to the first substrate and the second substrate by heat treatment.

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